The new approach to assignment of ASFA categories--introduction to the fourth special issue: clinical applications of therapeutic apheresis.

The American Society for Apheresis (ASFA) Apheresis Applications Committee is responsible for a review and categorization of indications for therapeutic apheresis. The results of the review process were previously published in 1986, 1993, and 2000 as the ASFA Special Issues. The ASFA categories consist of categories I through IV, and category P (pending). This article describes the novel methodology, based on structured systematic review of the published literature, used to assign categories for indications for therapeutic apheresis. This is the first time each entity is presented as a fact sheet, which summarizes the evidence for the use of therapeutic apheresis. A detailed description of the fact sheet format and the individual fact sheets for categories I through III and category P are presented in the main article of this Special Issue. The diseases assigned to category IV are discussed in a separate article in this issue. Information on how the Apheresis Applications Committee proposes to include new diseases for category assignment is also provided.